Dear Lady of the Lake,
We have a private, single drinking water intake that takes in water from Clear Lake and provides tap water and wash water to our lakeside summer vacation cottage. With the drought and algae concerns this year, what do I need to know about being able to safely drink and use our water?
— Carly at the Cottage
Dear Carly,
Thank you for reaching out about this topic! I am also glad that you are asking this topical question and thinking ahead. Right now is a good time to be preparing for the summer season, with expected low water levels due to drought combined with warm summer temperatures, we can expect a very heavy cyanobacteria season. Heavy cyanobacteria means that drinking water systems, both public and private, will require more attention to operate safely.
Let’s remind ourselves that cyanobacteria are not algae, they are in completely different categories in the “biological kingdoms of living things.” Cyanobacteria, since they are bacteria, are in the monera kingdom with other prokaryotic bacterias. Green algae, or phytoplankton are grouped into the protista kingdom.
In Clear Lake, the green algae does not produce toxins or pose human health concerns when exposed or ingested. Some types of cyanobacteria in Clear Lake, especially in the warm and long days of summer and fall, produce high concentrations of toxins that can pose health concerns to humans and pets when exposed to the skin or ingested.
Not every person responds the same way to a cyanobacteria exposure, it’s comparable to allergies in that everyone is affected differently and has different symptoms. Some people never notice when they swim in water or ingest a small amount of water with cyanobacteria and some people go wading one time and get rashes or flu-like symptoms for a day or more.
These cyanobacterias are the main concern for small, individual drinking water systems on Clear Lake, as high concentrations of cells, and the toxin they produce, can overwhelm smaller systems, making the filtering and chemical treatments uneffective, increasing the potential for exposure through drinking or bathing water.
Understanding what type of drinking water system you have
To reiterate, today’s column will mostly focus on small, or single, private, individual drinking water systems (less than 14 connections or homes). These systems start with an intake pipe, usually on a private, residential property, that takes water directly from Clear Lake, and into a small treatment or filter system on your property or inside your home. Sometimes a few neighbors, cottages, or a small resort or mobile home estate will have private systems with less than 14 connections. These are all considered small, private, individual, or very small drinking water treatment systems.
These types of small, individual systems are not regulated by the State or the County. Safe operation, maintenance, and monitoring of these systems is provided by the homeowner or property manager.
Today’s column will not focus on large public or private purveyor drinking water systems. If you pay a bill to a company that treats and distributes your drinking water to your home, and your neighbors, through a pipe, then you are on a public, or municipal, or large private company drinking water treatment system. These systems are fully regulated by the State’s Drinking Water Division.
If you do have municipal, public, or large private drinking water that you pay a company every month or every other month, I will refer you to several references where you can find more information about those types of systems and the monitoring that is done.
I wrote about drought and drinking water systems, and cyanobacteria, in my “Distressed about Drought” column on July 25 2021. This column would be a good refresher to drought impacts on larger drinking water systems.
To access your public or large private system monitoring data, as well as other system information, visit the CA Drinking Water Watch website. This website includes information like system details, facilities, monitoring results and schedules, violations or enforcement actions, and copies of consumer confidence reports. This resource is provided by the Drinking Water Division of California and provides information for all state-regulated systems, not just those with intakes on Clear Lake.
To learn about cyanobacteria monitoring that is done on these public, municipal, or large private systems, you can watch an informative County of Lake Water Quality Wednesday webinar from the Lake County Water Resources, Public Health Department, and Special Districts that was recorded on Sept. 1, 2021.
While I am embedding this video here, you can also find this recording on the County of Lake Water Resources website, under the Cyanobacteria Tab, or on the County of Lake YouTube channel.
Recording of Water Quality Wednesday Webinar September 1, 2021. Clear Lake Drinking Water and Cyanobacteria. Presenters included Rachel Kennard (UC Davis and Cal Rural Water Association) and Sarah Ryan (Big Valley EPA).
Unregulated individual drinking water systems
If you have been out on the lake so far this season, you might have noticed that it looks pretty good. Some areas are even blue and very clear. While so far things seem relatively fine, we should prepare for a point in the season when we will see an interaction of quantity (low lake levels) and quality (extremely severe blooms of algae and cyanobacteria) impacting small, individual drinking water systems.
The upcoming low water levels, combined with hot and long summer days might cause trouble for small or individual systems with smaller treatment or filter capacities. These systems are unregulated by any local or state government, and not monitored for effectiveness or performance. Therefore a household may be paying a significant amount of money for a service provider to “be treating” their water that comes directly from Clear Lake, but there is no oversight to these type of systems or laws to protect the consumer, like there are for public, municipal, or professionally large treatment systems and purveyors.
The owner of the system is the responsible party for ensuring these systems are maintained and serviced regularly. Additionally, some small treatment service providers are unfamiliar with the unique and special needs of being a small, individual treatment system on Clear Lake, a unique lake that is enriched with 500,000 years of organic matter and suffers from very frequent and sometimes severe toxic cyanobacteria blooms.
These small, individual systems are usually capable of providing safe drinking water from natural water sources, but during the late summer, when Clear Lake experiences frequent and severe cyanobacteria bloom events, the amount of organic material in the water can overwhelm these private, small systems. Even boiling or chlorinating the water will not remove cyanobacteria cells or the toxins they produce, in fact these methods make the toxins more pronounced and cause more exposure risk.
Public,municipal and large private professional systems on the other hand, are much larger, with multiple layers of treatment and filters in place that adequately remove cyanobacteria cells from the raw water of Clear Lake, before entering the chemical treatment process. In fact, in 2021, the State of California Drinking Water Division of the State Water Resources Control Board, mandated cyanobacteria monitoring of all the 18 public, municipal and large private drinking water systems on Clear Lake. Every system that was monitored at the tap resulted in no exceedances for cyanobacteria microcystis toxins and were safe for drinking.
Be aware of drinking water advisories
Last year the concentrations of toxins produced by some cyanobacteria in Clear Lake were sampled at such high, concerning levels that the Public Health Officer issued an advisory, followed by a news release, urging some households on small, private, individual systems in certain areas of the lake to stop drinking their water.
This release was issued on Sept. 16, 2021, when the summer months and low water levels had created perfect conditions for exceptionally large and severe cyanobacteria blooms to occur. People on private, small individual systems, in mostly the Oaks and Jago Bay area, were warned to not drink the water from their tap, only if they were part of a small system of 14 connections or less, or had a single intake directly from the lake into their home and managed their own drinking water treatment system.
The advisory also recommended homeowners to purchase their drinking water or fill up clean containers from alternative filling stations provided by commercial or public treatment systems. These companies were Konocti Municipal Water Company (Kelseyville) and Golden State Water Company (Clearlake). These two large private, professionally-treated drinking water purveyors were providing treated, potable water for those in areas who had private intakes providing temporarily unsafe water.
It really is amazing how the community and businesses come together in times of crisis to support one another; we are grateful to these companies to step up to provide safe drinking water sources for free during a time of need.
Be prepared and get help monitoring your small or individual drinking water intake
If you or your household is on one of these small, individual systems (less than 14 connections) then you might want to be more vigilant this year about monitoring your drinking water at the tap. Luckily, local tribal organizations and partners have developed a program to monitor and track this information at no cost to the homeowners.
Big Valley Band of Pomo Indians, working with Tracking California, the Institute of Health, and the Drinking Water Division of the California Water Resources Control Board, are currently working on a grant program to monitor cyanobacteria — and other contaminants — in private, small, individual drinking water systems of Clear Lake. This program is called the California Water: Assessment of Toxins for Community Health Project, or Cal-WATCH. Visit the Tracking California Cal-Watch Project website here.
The Cal-Watch program started last year in 2021, and Big Valley EPA Director, Sarah Ryan, and the Cal-Watch team have learned a plethora of information about public health when it comes to private, individual drinking water systems on Clear Lake.
The results from the 2021 Cal-Watch project will be presented this coming Wednesday. April 13th 2022, at 6 p.m. at an online Water Quality Wednesday Public Learning Forum. This webinar is hosted by the County of Lake, Water Resources Department, and Public Health Department.
This webinar is free, open to the public, and will be accessible through zoom, County of Lake Facebook Live, and through PegTV (Mediacom Channel 8). The webinar will be recorded and available on the County of Lake YouTube channel and Water Resources Department Cyanobacteria webpage. To access the webinar through zoom, use Webinar ID: 930 6092 7543 and Pass code: 466041.
This webinar will present the data and results from monitoring for contaminants in private, small drinking water systems on Clear Lake, in addition to some well monitoring data. The presenters will talk about their findings from a monitoring during a drought year, which will be applicable for this coming summer during the third year of drought conditions.
What to do?
Now, if you are like Carly and her cottage, and your small, individual private drinking water system is questionable or incapable of effectively treating Clear Lake source water during high bloom events, such as were experienced last year, there really is not an easy fix. There is no magic small treatment system that can handle the conditions Clear Lake sometimes contains.
The absolute best and safest solution would be to try to connect to a municipal, public or large private system that is regulated and mandated by the state to monitor and remove cyanobacteria from their systems. Currently large systems, adjacent to areas with no municipal water sources, are looking at plans for expanding their connections into these areas. If you are concerned or curious, you can call the treatment purveyor closest to you and ask about these plans and feasibility of including your home as a connection. If the company knows that they might have customers in the area, it might increase the rate and speed of expansion of their system to your area.
The next solution, if the first one isn’t possible, is to be prepared for not using your drinking tap water when a significant and severe bloom occurs and a public health advisory is released for your area. This doesn’t happen every year, but is more likely to occur during times of drought and longer, warmer summers. Again, this recommendation is only for small, individual private intake systems that are located in areas identified in a public health advisory notice. This does not apply to large private, public or municipal drinking water systems, as their tap water is regularly monitored and safe to drink.
Being prepared means having extra gallons of drinking water on hand as well as having an alternative source for drinking water. Make sure to have clean containers and reliable transportation to get those containers filled if needed.
If you don’t have access to reliable transportation to get to and from a filling station, contact your neighbors, family, or friends, to see if you can pool resources, or combine efforts, to get clean, safe water to drink.
How do I know if I am close to a large private, public, or municipal drinking water provider?
To find out where the public, municipal, or large drinking water system providers are located around Clear Lake, and the rest of Lake County, you can visit the Tracking California Drinking Water Mapping Tool online.
This tool provides information on the locations of Community Drinking Water sources, that include both groundwater and surface waters, like Clear Lake. This is an interactive mapping tool, using an ESRI-based platform, so it deserves some time exploring to find out the full extent of information and data that the tool can provide. I suggest turning on and off layers and making different selections to see what type of information is available on the map and what it can tell you.
The Tracking California Drinking Water Tool is available at the following website (as of April 5, 2022).
I have taken an excerpt of the mapping tool showing the Community Water Systems layer selected. This shows the companies, public, municipal, and large private systems that are located around Clear Lake. If you live outside these highlighted areas, you may receive your water from a groundwater provider, a private well, or you may be on an unregulated, small, individual system with less than 14 connections.
If the latter is the case, please be prepared for the summer cyanobacteria season especially when it comes to having a safe, drinking water source for you, your family, your pets, and your home.
Sincerely,
Lady of the Lake
Angela De Palma-Dow is a limnologist (limnology = study of fresh inland waters) who lives and works in Lake County. Born in Northern California, she has a Master of Science from Michigan State University. She is a Certified Lake Manager from the North American Lake Management Society, or NALMS, and she is the current president/chair of the California chapter of the Society for Freshwater Science. She can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..
Lady of the Lake: Private, small and individual drinking water systems
- Angela De Palma-Dow
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